Apparatus for generation of gas



June 1967 ELMARMANFRED HORN ET AL 3,323,873

APPARATUS FOR GENERATION OF GAS 8 Sheets-Sheet 1 Filed Jan. 9, 1963 INVENTORS: RINKES,

ELMAR-MANFRED HORN, KONRAD LANG, HANS D/E TR/CH VO/G T.

ATTORNEY June 1967 ELMARMANFRED HORN ET AL 3,323,873

APPARATUS FOR GENERATION 0F GAS Filed Jan. 1963 8 Sheets-Sheet ,kfjg I F/G 4 r n :1 i L: HA 3 F/G. 3a

A-A A-A INVENTORS.

ELMAR-MANFPED HORN, KONRAD LANG, HANS P/NKES, DIE TR/CH VO/GI BY ATTORNEY June 6, 1967 ELMARMANFRED HORN ET AL APPARATUS FOR GENERATION OF GAS 8 Sheets-Sheet 3 Filed Jan. 9, 1963 INVENTORSF NG, HANS R/NKES ELMAR-MANFRED HORN, KONMD LA DIE TP/CH VO/GT.

A TTOPNEY June 6, 1967 ELMAR-MANFRED HORN ET L 3,323,373

APPARATUS FOR GENERATION OF GAS Filed Jan. 9, 1963 8 SheetsSheet 4 INVENTORS ELMAR-MANFRED HORN, KONRAD LANG, HANS R/NKES,

0/5 TR/CH VO/GT. BY

A 7' TORNE Y J1me 1967 ELMAR-MANFRED HORN ET AL 3,323,873

APPARATUS FOR GENERATION OF GAS 8 Sheets-Sheet 5 Filed Jan. 9 1963 INVENTORS.

ELMAR-MANF'RED HORN, KONRAD LANG, HANS P/NKES, Y

DIE TR/CH VO/GT.

ATTORNEY J1me 1967 ELMAR-MANFRED HORN ET AL 3,323,873

APPARATUS FOR GENERATION OF GAS Filed Jan. 9, 1963 8 Sheets-Sheet 6 INVENTORS.

ELMAR-MANFRED HORN, KONRAD LANG, HANS R/NKES,

D/ETR/CH VO/GI BY ATTORNEY June 6, 1967 ELMARMANFRED HORN ETAL 3,323,873

APPARATUS FOR GENERATION OF GAS Filed Jan. 9, 1963 S Sheets-Sheet 7 FIG. 70

INVENTORSI ELMAR-MANFPED HORN KONRAD LANG, HANSv RINKES DIE TR/CH VO/GT BY ATTORNEY June 6, 1967 ELMARiMANFRED HORN ET AL 3,

APPARATUS FOR GENERATION OF GAS 8 Sheets-Sheet &

i Q I: & Q

INVENTORS. E LMAR-MANF RED HORN, KONRAD LANG, HANS R/NKES D/ETR/CH VO/GZ BY A TTORNEY United States Patent 3,323,873 APPARATUS FOR GENERATION 0F GAS Eirnar-Manfred Horn, Aachen, Konrad Lang, Leverkusen, Hans Riuires, Dormagen, and Dietrich Voigt,

Coiogne-Muiheim, Germany, assignors to Far-heritahriken Bayer Aktiengeselischaft, Leverltnsen, Germany,

a corporation of Germany Filed Jan. 9, 1963, Ser. No. 250,395 Claims priority, application Germany, Jan. 10, 1962, F 35,738; Dec. 22, 1962, F 38,641 8 Claims. (Cl. 23--281) The present invention relates to an improved process and an apparatus for the production of gases, in particular hydrogen.

The process and the apparatus according to the inven tion offer advantages in cases where difiiculties associated with the shipment prohibit the use of large-size apparatus and heavy steel cylinders. Besides, the herein described process and apparatus are advantageous for the following reasons:

(1) The apparatus operates without any danger, i.e. a dangerous pressure rise in the apparatus according to the invention does not occur even if a conduit is closed;

(2) The starting products are in most cases easily and safely transportable;

(3) Recourse is possibly, at least to some extent, to a naturally occurring starting material, namely water;

(4) The starting products can be supplied in very cheap containers so that these can be destroyed after a single use;

(5) The construction of the apparatus according to the invention is very simple which allows easy cleaning and re-use. The attendance of the apparatus is possible by unskilled personnel and under unfavourable surrounding conditions.

The herein described process and apparatus can be adopted with advantage in the generation of hydrogen, e.g. in the gassing of meteorological balloons, i.e. balloons carrying meteorological instruments, with hydrogen in the open field.

Other gases e.g. acetylene, carbon dioxide and chlorine can also easily be produced by the novel process and the apparatus according to the invention.

Until recently e.g. hydrogen was produced in the field by the reaction of caustic soda solution with aluminum or ferro-silicon.

The aforesaid prior art process involved serious drawbacks: the caustic soda led repeatedly to burns on operating personnel, the reaction took place with strong evolution of heat and had to be conducted in pressure vessels, the waste products were strongly alkaline and their safe disposal not always possible.

More recently recourse has been had to the metal hydrides for the generation of hydrogen. The hydrides and mixed hydrides of the elements of the principal Groups I to III of the Periodic Table are known to react with water with formation of hydrogen. With alkali metal and alkaline earth metal hydrides as well as with alkali-aluminum hydrides (alanates) the reaction proceeds very lively, in some cases even turbulent to explosive. Lithium alanate, LiAlH tends to ignition on contact with water. The hydrolysis proceeds quantitatively with the hydrides mentioned, as long as no secondary effects obstruct it, such as for example the formation of scarcely soluble by-products: in the hydrolysis of calcium hydride there are almost always considerable amounts of hydride included in the calcium oxide or hydroxide reaction products. The yield drops considerably as a result. The high reaction velocity of the aforesaid hydrides is coupled with a large heat of reaction, which leads to a strong heating up of the reacting mixture.

Patented June 6, 1967 The alkali metal borohydrides (boronates), on the other hand, are less reactive to water. This applies especially to technically produced sodium borohydride and potas sium borohydride, which are soluble in water with only small decomposition. To bring about quantitative hydrolysis, the solutions of the borohydrides must be either acidified or mixed with catalytically active heavy metal salts.

Hitherto, for practical application, only calcium hydride has been used. Its use involves disadvantages:

(1) The heat of the reaction:

is considerable, and the hydrogen escaping from the reaction mixture, if it is not specially cooled in a way involving expense, carries large amounts of Water vapor into the balloons and thus reduces their carrying capacity. At greater heights it can cause icing up of the balloon interior leading to destruction of the balloon skin;

(2) As secondary product a strongly alkaline suspension of calcium hydroxide (milk of lime) occurs. Spray reaching the eyes can lead to serious burns. Analogous considerations apply to the hydrolysis of the alkali metal hydrides.

The known, less vigorously proceeding hydrolysis of borohydrides, especially that of the technically readily obtainable and cheap sodium borohydrides, is of no value for the afore-described purpose without special measures.

The reaction catalyzed by heavy metal salts carries with it the advantage that 1 kg. of sodium borohydride generates about 23 (normal cubic meters) of hydrogen, as against 1.07 Nm of theoretical yield with calcium hydride. Since, however, the reaction only proceeds from 60 to C. at useful speed, which rapidly rises on account of the reaction heat, and moreover extraordinarily large foam formation takes place which cannot be broken by antifoaming agents, the reaction has still not been utilized in practice up to now. The acid decomposition of borohydrides proceeds smoothly only with dilute mineral acids. For use on a field scale dilute mineral acids are ruled out, however, on account of their corrosive properties, and hazard to health.

The present invention is concerned with a technical method of producing gases by the reaction of solids and liquids and with an apparatus for carrying out this reaction. In particular the invention relates to the production of hydrogen by the reaction of mixtures of borohydrides and boric oxide with water.

It is an object of the present invention to provide an improved and efiicient process of producing gases by the reaction of solids and liquids.

It is another object of the present invention to provide a new process of producing hydrogen by the reaction of mixtures of borohydrides and boric oxide with water.

It is still another object of the invention to provide an apparatus for carrying out the reaction of solids and liquids for the production of gases.

Further objects will become apparent as the following description proceeds.

The apparatus according to the invention allows the production of gases in simple manner by the reaction of solids and liquids. The herein described process of producing gases and the operation of the new apparatus will be illustrated by way of example with reference to the production of hydrogen from alkali metal borohydrides, boric oxide and water.

In accordance with the invention it has been found that the decomposition of borohydride-boric oxide mixtures with water to form hydrogen is suitable under certain preconditions. Boric oxide and sodium borohydride can be ground together in the well dried state and then compressed into moldings, e.g. pellets and tablets, which have an unlimited keeping property on storage under conditions excluding moisture, and react with water even at relatively low temperatures.

Suitable experiments have now revealed that the reaction of sodium borohydride with boric oxide and water proceeds completely and without undesired sideeffects, if certain conditions are maintained, in a manner useful for the generation of hydrogen in the field.

If moldings of an NaBH /B O mixture are thrown into much water, then a vigorous reaction takes place at the water/pellet interfacial surface with formation of hydrogen. Simultaneously, however, considerable amounts of borohydride and boric oxide dissolve without reaction and, moreover, water diffuses into the interior of the pellets, reacts only there and bursts open the pellets. The result is that only a relatively small part of the reaction mixture, about 30 to 60%, reacts with a useful velocity, while the rest only reacts very slowly; this efiect can be explained by the weakly acid nature of the boric acid.

On the other hand, if only little water is added to the solid reaction mixture, then likewise no rapid quantitative reaction takes place since this time, as a reaction byproduct, solid sodium tetraborate hydrates are formed expanding to a voluminous foam by the hydrogen and retaining the starting material.

For the practical carrying out of the hydrolysis, the known gas evolution apparatus, adapted, for example, from Kipps apparatus, cannot be used since it is mostly a matter of swinging between supplying either too much or too little water, with the above-mentioned consequences; frequently parts of the pellets fall into the reaction-water supply chamber and there disturb operation by a steady evolution of gas, whereas with other ways of carrying out the reaction narrow pipes are easily blocked up by sodium tetraborate-hydrates. The known forms of apparatus also mostly fail in the requirement for the simplest possible construction.

The invention will hereinafter be further described with reference to the accompanying diagrammatic drawings, wherein FIGURE 1 is a sectional view of an apparatus according to the invention with 2 generators connected to one washing vessel;

FIGURE la is a plan view of the apparatus shown in FIGURE 1, with 4 generators connected to one washing vessel;

FIGURE 2 is a sectional view of a portion of the apparatus shown in FIGURE 1;

FIGURE 2a is a horizontal section on line AA of FIGURE 2;

FIGURE 2b is a horizontal section on line BB of FIGURE 2;

FIGURE 3 shows, in sectional view, another embodiment of the generator with 3 perforated tubes;

. FIGURE 3a is'a horizontal section on line AA of FIGURE 3;

FIGURE 4 shows, in sectional view, another embodiment of the apparatus of the invention, the generator being concentrically surrounded by the washing vessel;

FIGURE 4a is a horizontal section on line AA of FIGURE 4;

FIGURE 5 is a perspective view of the apparatus shown in FIGURE 4;

FIGURE 6 is a perspective view of the apparatus shown in FIGURE 5 without the reaction assembly;

FIGURE 6a shows, in a perspective view the reaction assembly consisting of the reaction chamber, a perforated tube and the horizontally extended plates, each with at least one operator;

FIGURE 7 is a sectional view of a third embodiment of the generator;

FIGURE 8 is a sectional view of still another embodiment of the apparatus of the invention;

FIGURE 9 is a perspective view of the apparatus shown in FIGURE 8;

FIGURE 10 is a sectional view of the apparatus used for carrying out the processes described in Examples 9 and 10, with the dimensions in mm.;

FIGURE 11 is a sectional view of the apparatus used for carrying out the processes described in Examples 3, 4, 5, 6, 7 and 8, with the dimensions in mm.

The new apparatus for the production of gases by reaction of solids with liquids, especially alkali metal borohydrides with boric oxide and water, has at least one reaction chamber 1, which consists of a vessel or housing 2 with e.g. circular, elliptical or threeor more-cornered base, in which at least one substantially vertical upwardly directed tube 3 is inserted with perforated wall surfaces. Under the reaction chamber 1 are one or more substantially horizontally extended plates 4, 5, 6 each with at least one aperture 7, 8, 9. The reaction chamber is mounted in a vessel 10 open at the bottom, the cross section of which corresponds to that of the reaction chamber 1 or that of the combined chambers, and is closed at its top side 11 and provided with a gas outlet pipe 12 and optionally a filling opening 13. The gas outlet pipe 12 leads into a gas washing vessel 14, which is spatially separated from the vessel 10 or surrounds it. The washing vessel 14 is open at the bottom, closed at the top. At the top it contains a known mechanical device 15 for removing liquid water entrained; in the gas outlet 16 which may be constructed as a handle. A drying column 17 may be incorporated.

Several gas evolution vessels can be connected to one washing vessel, as is apparent from FIGURES 1 and la.

A previously formed mixture of alkali metal borohydride and boric oxide is charged into the reaction chamber 1, the reaction assembly 1 to 9 may be installed in vessel 10, the vessel 10 connected with washing vessel 14 is lowered into water up to the immersion level 18, and the immersion level of the inlet pipe 12 is so adjusted in the washing vessel that during the reaction no hydrogen is evolved at the bottom of the vessel 10 in the form of large bubbles.

The production of hydrogen by reaction of sodium borohydride with boric oxide and water with reproducibly good yields is carried out completely without danger, if the apparatus illustrated in principle by FIGURES 2, 2a and 2b, is used. The vessel 10, referred to in the following as the generator, contains as the essential part at least one reaction chamber 1. This possesses usually circular crosssection, but can also have e.g. elliptical or threeor morecornered shape, the latter especially when several such reaction chambers are arranged side by side in one generator. The bottom of the reaction chamber is either arranged horizontally or sloped downwardly towards the middle like a funnel. Into the reaction vessel 2, expediently symmetrical to the cross-section, at least one approximately vertical upwardly directed pipe 3 is arranged which is open at the bottom and optionally closed at the top. The wall of the pipe 3 is provided with openings. If several reaction chambers are combined in larger devices, then the partitions between the individual reaction chambers can be omitted, if desired, resulting in a reaction chamber 20, containing several perforated tubes 21, 22, 23 as represented schematically in FIGURES 3 and 3a. This apparatus feature is of advantage in the construction of generators for large quantities of hydrogen.

The size of the reaction chamber 1 is so chosen that it offers enough space for the acceptance of the molded borohydride-bon'c oxide mixture. The space from the wall of the reaction chamber 1 to the wall of the fitted tube 3 is, in the interest of a high reaction velocity, advantageously not larger than 8 cm. When working with larger reaction chambers that correspond to this size, then several perorated tubes are arranged in the chamber. The diameter of the inserted tube 3 lies at l to 5 cm., the size of the openings in 3 lies at about 0.25 to 2.5 cm. according to the size of-the borohydride moldings, the degree of perforation of the wall, ie, the ratio of the total area of the apertures to the total surface of the pipe wall is at least At intervals of 1 to 10 cm. each, there are arranged below the reaction chamber 1 up to six plates 4, 5, 6, their shape corresponding approximately to the cross-section of the generator vessel 10; the plates carry one or more holes 7, 8, 9 whose diameter is at least 1 cm., the holes of the various plates being staggered as much as possible from each other. The plates serve to recover particles of moldings dropping from the reaction chamber 1 through the pipe 3 and to retain them for the reaction. The openings in the plates must ofier no resistance to movement of the water column in the lower part of 10. It is expedient that the plates be connected with one another and with the reaction chamber by rods, to form a reaction assembly 1 to 9.

The generator vessel 10 is in principle a tube closed at one end, having at the closed upper part a gas exhaust tube 12 and optionally a filling opening 13. On the outside a mark 18 is arranged for the immersion level in water, in the preferred embodiment this line being identical with the upper limit of borohydride filling in the reaction chamber, but being possibly different therefrom. The height of ves sel 10 above the level mark 18 is dictated by the height of foam formation in the reaction, being less than 30 to 40 cm. with corresponding construction of the reaction chamber 1. The extent of the generator 10 below the line 18 is determined by the pressure loss of hydrogen in the total apparatus, by the immersion depth of the gas exhaust pipe 12 in washing vessel 14, as well as the back pressure of the device to be fed with hydrogen and the pressure drop in the pipes outside the device.

The reaction assembly 1 to 9 can be fixed firmly in the. generator 10. The charging of the device is then carried out through the filling opening 13. In a preferred embodiment the assembly 1 to 9 in the generator 10 is fixed by a plug fastening so that it can be taken out of the generator 10 from the bottom. The cleaning of the apparatus is thereby facilitated; the charging opening 13 is omitted in this arrangement (cf. FIGURES 5, 6 and 6a).

From the generator vessel 10 a gas exhaust pipe 12 leads into the Washing vessel 14. The length of 14 i expediently the same as that of the generator 10, or greater, its diameter being chosen not too small, so as not to carry over too much water in the form of drops. The Washing vessel can, according to FIGURE 1, be provided -wfth several inlet pipes, so that several generator can be connected together for the evolution of larger yields of hydrogen. The vessels 10 and 14 are so connected together that no mutual displacement can occur. For reason of space economy the washing vessel 14conveniently concentric-can be arranged around the generator 10, as shown again in FIGURES 4, 4a, 5, 6, and 6a. To improve the washing action, the gas outlet pipe 12 has expediently the shape at its lower end 12a as illustrated in FIG- URES 4 to 6. In this way a better distribution of the gas is achieved; by the incorporation of guide plates 17:: an effect, similar to a mammoth pump, provides an additional circulation of the Water in the Washing chamber. In the arrangement in FIGURES 4, 5, 6, and 6a the reaction assembly is fixed in the generator 10 by a plug fastening and can be taken out from the bottom. The generator 10 possesses in this case no upper filling opening.

The Washing vessels 14 expediently possess in their upper part a mechanical Water spray guard. Constructions, known in the literature, are applied for this purpose.

In order to dry the gas escaping from the washing vessel 14, a drying column 17 can be incorporated in the gas outlet 16, expediently constructed as a handle. As a filling for the drying column 17 there may be used the usual drying agents, especially zeolites, and silica gel and granulated calcium chloride, the lower part of the column being filled with silica gel and the upper for after-drying of the gas being filled with dehydrated zeolite, for the sake of economy.

The devices are preferably made of metal, but synthetic resins and glass can also be employed. Metal can also be employed which is covered with rubber or synthetic resin or protected against corrosion in conventional manner.

In operation, the reaction chamber 3 is filled with borohydride-boric oxide mixtures in form of moldings, e.g. tablets. One starts expediently from a finely ground intimate mixture, containing the starting materials in the molecular ratio of 2 alkali metal borohydrid-e:1 boric oxide. To facilitate the shaping, a small amount of talcum can be added to the mixture. It is advantageous, but not necessary, to employ the borohydride-boric oxide in the aforementioned ratio; proportions departing therefrom can also be chosen.

The filling of the generator 10 proceeds either (FIG- URES 1 and 2) by the filling nozzle 13 or directly into the reaction assembly 1 to 9 (FIGURES 4 to 6). To reduce foam formation the reaction mixture is augmented with about 0.1 to 5 percent by weight of a commercial anti-foaming agent. Anhydrous tributyl phosphate has proved especially suitable, which can be sprinkled directly onto the moldings without affecting their stability on storage. After the opening 13 has been closed, or the assembly has been replaced in the generator, the generator 10 is immersed in water together with the washing vessel 14 up to the mark 18. The water enters from the bottom into both vessels and finally through the pipe 3 into the reaction chamber 1. The amount of the water penetrating into the reaction chamber is also determined by the immersion depth of the gas outlet pipe 12 in the washer 14. By the starting hydrogen evolution, the water level is pressed down through the pipe 3 out of the reaction chamber, the parts of moldings thereby expelled being held back by the plates 4 to 6, especially by 4, completing here their reaction. The water remaining in the reaction chamber 1 reacts with the disintegrating moldings. The evolution first passes through a velocity maximum, causing a pressure rise in the generator, which depresses the water level almost to the lower end of the vessel 10, then the hydrogen evolution proceeds with relatively uniform velocity. The water level thereby remains approximately at a height between the plate 4 and the lower edge of the reaction chamber 1. Through the special construction of the reaction assembly, in the reaction chamber 1, only the minimum amount of water necessary for the reaction and the avoidance of an excessive formation of foam is found. Thus too strong a dilution of the reaction mixture and consequent reduction of yield, is excluded. The temperature of the reaction mixture rises during the reaction to to C. The hydrogen leaves the generator 10 at a temperature of 60 to 70 C., is conducted through pipe 12 into the Washing vessel 14 and cooled here to about 25 to 30 C., whereby the content of water vapor in the gas falls considerably.

Of considerable importance for the undisturbed course of the hydrogen evolution is the immersion depth of the pipe 12 in the water present in the washing vessel 14. This immersion depth determines not only the constant pressure in generator 1i but also influences the amount of the water penetrating into the reaction chamber at the beginning, and therefore the Whole course of the reaction. The optimum immersion depth of 12 in 14 is a complex quantity; it is determined inter alia by the composition of the reaction mixture, the pressure with which the moldings are compressed, the size of the moldings, the shape of the reaction chamber 1, the distance of the pipe 3 from the chamber Wall, the size and number of the openings in pipe 3, the cross-section of the gas outlet pipe 12 and the back pressure from outside the apparatus. The optimum immersion depth is determined by short tests. The adjustment of the apparatus to optimum function is carried out by altering stepwise the immersion depth of the pipe 12 in a model, for long enough until at the reaction velocity maximum (at the beginning of the reaction) no more large gas bubbles come out at the bottom side of the generator 10. With this adjustment optimum reaction velocity is simultaneously obtained. The immersion depth, determined on the model, can then be transferred to the other devices from the beginning, provided that no alterations occur in the once selected conditions. A further criterion for optimum adjustment is the test for maximum foam height, which is to be no greater than 20 cm., measured from the upper edge of the filling in chamber 1.

The hydrogen cooled in washing vessel 14 is freed in a water-spray separator of conventional type, from drops of entrained water.

If the hydrogen is to be especially dry, the gas outlet 16, shaped as a handle, is filled with a drying agent 17. In order to obtain no additional pressure loss by sticking of liquefying effects, a drying agent is preferably used based on silica gels or zeolites, which may be applied in a separate or mixed form. The dew point can thus be lowered to considerably below C. Besides, the very cheap calcium chloride can also successfully be used for this purpose.

According to a preferred embodiment of the new apparatus the reaction chamber 1 (cf. FIGURE 7) is connected to a sinkable float in the form of perforated hollow member 26 by means of round rods 24. The dimensions of the hollow member are chosen so large that the generator assembly, which is filled with moldings and consists of the reaction chamber 1, at least one substantially vertically extended, perforated tube 3 which is open at the bottom and may be closed at the top, the hollow member 26, the cover 27, at least one bore 29, one or several bores 25 and the round rods 24 connecting the reaction chamber 1 and the hollow member 26, initially floats on the surface level of the water, when the generator immerses into water. In order to secure a slow immersion rate of the hollow member 26 after the immersion of the apparatus so that the moldings are gradually wetted, the bottom side of the hollow member 26 is provided with one or more bores 29, preferably in the cover 27. Besides, the upper rim of the hollow member 26, i.e. the upwardly directed cover surface thereof, is provided with several small bores 25 so that the air can escape undisturbed. To facilitate cleaning the bottom side of the hollow member 26 is provided with cover 27 which can be closed.

When the generator immerses into water the reaction chamber, which is supported by the hollow member 26 filled with air, floats on the surface level of the water without the layer of moldings being contacted with water. Water flows into the hollow member 26 through the opening or openings 29, while the displaced air escapes through the bores 25. At the same time the reaction chamber 1 together with the hollow member 26 moves down at a rate which is determined by the size of the opening 29 and/or the size of the bores 25. At the same rate the first moldings are wetted with water. In this manner the evolution of gas sets in at a predetermined rate. As the reaction chamber 1 and the hollow member 26 move down further the generator assembly is finally placed with the bottom side of the hollow member 26 on the interposed, readily removable locking bar 28 of the generator vessel and is thereby ultimately fixed in its height, since the hollow member 26 which is now filled with water no longer allows floating. After the reaction is complete the cover 27 is preferably removed from the hollow member 26 in order to remove the water from the hollow space.

In the aforesaid manner it is realized that in the production of large amounts of hydrogen, e.g. 2 to 6 m. per

batch, the evolution of hydrogen starts at a controlled rate, i.e. not intermittently, and proceeds at maximum speed, since the initial maximum in the evolution of gas is considerably decreased. The preferred form of the generator assembly can be used in all of the above described apparatus which are appropriately modified by the arrangement of a locking bar 28.

A preferred embodiment wherein the washing vessel 8 and the generator vessel 10 are assembled into a single unit, is shown in FIGURE 8.

A gas outlet pipe 12 extends from the generator vessel 10 into the washing vessel 14 which is arranged, preferably concentrically, about the generator vessel 10. To improve the washing effect, the gas outlet pipe 12 is preferably provided in the form shown in FIGURES 8 and 9. By such an arrangement the distribution of the gases evolved is improved. Installation of guide plates 17a brings about an effect similar to that of an air-lift pump, thus securing additional circulation of the water which can be further promoted by the arrangement of openings 31 (cf. FIGURE 8) in the generator jacket 30. The upper part of the washing vessel 14 is preferably equipped with a mechanical spray-water separator 15, and a gas outlet means 16 which may be provided with a drying column 17 as described above.

The apparatus of the invention is operated e.g. in the production of hydrogen, by detaching the locking rod 28 which is held e.g. by a slide lock, from the generator vessel 10, withdrawing the generator assembly consisting of the members 1, 3, 24, 25, 26, 27 and 29 from the vessel and feeding the requisite quantity of the mixture of borohydride and boric oxide to the reaction chamber. Thereupon the filled generator assembly is pushed into the generator vessel 10, fixed by fitting the locking rod 28 and the entire generator is immersed into water preferably e.g. up to the height of A (cf. FIGURE 8).

The production of hydrogen in the field by the present invention affords some important advances, in so far as:

(1) The borohydride-boric oxide mixtures employed as starting materials are safe to handle and of unlimited keeping qualities with exclusion of moisture. They can'be transported in very simple, light and cheap packages, such as e.g. welded polyethylene bags;

(2) The reaction of the 'borohydride mixtures with water proceeds in the apparatus according to the invention rapidly and in readily controlled manner. For the production of 200 litres of hydrogen in a small apparatus e.g. of the type shown in :FIGURE 10, 4 minutes are required for example. The production of 2 m. of hydrogen in an apparatus e.g. of the type shown in FIGURE 11 takes about 8% minutes;

(3) The borates occurring as by-products, mainly tetraborates, such as borax for example, are not injurious to health;

(4) The apparatus according to the invention is of simple construction. On account of its type of construction, accidents by explosion of the apparatus by blockages of pipes are excluded. It can be used safely by unskilled personnel and it is also applicable in very unfavorable external conditions, since it requires no additional apparatus. If containers of water are lacking, the generator can also be operated in brooks or ponds;

(5) The water need not be changed in between operations, but can be used repeatedly.

The apparatus of the invention can be used not only for the production of hydrogen from alkali metal borohydrides, boric oxide and water, but also for carrying out other reactions between solids and liquids, e.g. the reaction of calcium hydride and water to form hydrogen, calcium carbonate and hydrochloric acid to form carbon dioxide, ferrous sulfide and hydrochloric acid to form hydrogen sulfide, fresh optionally molded chloride of lime and hydrochloric acid to form chlorine, precipitated manganese dioxide and concentrated hydrochloric acid to form chlorine, optionally rod-shaped sodium nitrite and dilute sulfuric acid to form nitric oxide, aluminum carbide and water to form methane as well as calcium carbide and water which may he saturated with sodium chloride to form acetylene.

The process of the invention for producing gases other than hydrogenis carried out analogously to the production of hydrogen from alkali metal borohydride-boric oxide mixtures with Water, by using instead of a mixture of alkali metal borohydride and boric acid the corresponding solid starting products, e.g. calcium carbide or calcium carbonate in lumps, and using instead of water, the corresponding liquids e.g. hydrochloric acid.

The new process of producing e.g. acetylene or carbon dioxide in one of the apparatus shown in FIGURES 1 to 11 is accomplished by feeding e.g. lumpy calcium carbide (particle size about 10 to 70 mm.) or lumpy calcium carbonate (particle size about to 50 mm.) in an amount corresponding to the amount of acetylene and carbon dioxide respectively to be produced, into the reaction chamber of the respective apparatus. By the choice of an appropriate average particle size the velocity of the reaction with the corresponding liquid can be controlled within certain limits; any particles of smaller or larger size need not be separated oif.

The known reactions of fresh chloride of lime with hydrochloric acid or precipitated manganese dioxide with concentrated hydrochloric acid to form chlorine can be carried out in analogous manner. In this process it may be of advantage to use the solid starting products in form of moldings. Besides, the other aforementioned reactions for producing nitric oxide, methane or acetylene can be readily performed in the apparatus according to the invention without any difiiculty.

The processing of corrosive liquids is preferably carried out in apparatus having sheet metals which are lined with rubber or plastics or which are protected against corrosion in any other customary manner.

The apparatus and the process of the invention will now be further illustrated in the following examples without being restricted thereto.

Example 1 An apparatus furnished in glass or brass according to FIGURE 1 was employed. The reaction assembly 1 to 9 consisted of steel plate or brass. The diameter of 1 amounted to 9 cm.; its height was cm. The diameter of the tube 3 was 3 cm., the openings in the wall of 3 were about 1.5 cm. in size. 1 and 3 possessed circular crosssection. 3 cm. below the reaction chamber were 5 plates separated by 3 cm. intervals each, the holes 7, 8 and 9 were 1 cm. The total height of the assembly amounted to 30.5 cm., the light width'of the generator 9.5 cm., its total height 50 cm., the height above the immersion line (18) 19.5 cm., below this line 30.5 cm. The diameter of the outlet pipe 12 was 1 cm., dipping 14.5 cm. below the line 18. The diameter of the cylindrical washing vessel 14 was 13 cm., its height 50 cm.

The generator was charged with 175 g. of a mixture of sodium borohydride and boric oxide in the molar ratio of 2:1, compressed with a pressure of 4.5 to 5.5 tons to tablets with a diameter of 1 cm. and a height of 0.7 cm. The tablets contained tributyl phosphate as antifoaming agent. The drying column was filled with 100 g. of dehydrated zeolite granules.

The evolution of 200 litres hydrogen required 4 to 4% minutes. The gas temperature after the washing vessel was 25 to 30 C., after the drying column maximum 60 C. The water content of the gas corresponded to a dew point of below 8 C. (limit of measurement).

Example 2 An apparatus according to FIGURES 4 to 6a was employed. The size of the generator 10 and the reaction assembly 1 to 9 was the same as in Example 1. The diameter of the washing vessel 14 was 14 cm., its height 60 cm. The gas tube 12a dipped 14 cm. below the line 18.

The filling of the drying column 17 was identical with that in Example 1, and likewise the amount and composition of the borohydride mixture.

The evolution of the main quantity of hydrogen (91% of the theoretical) required about 4 minutes; the reaction velocity then dropped considerably. The gas temperature after the drying column was at most 60 C. The water content of the gas corresponded to a dew point below -8 C. (limit of measurement).

By using twice the amount of borohydride-boric oxide mixture, 400 litres of hydrogen were evolved in the course of 8 to 9 minutes.

Example 3 An apparatus of aluminum sheet, shown in FIGURE 11, was used. The reaction chamber was charged with 1740 g. of a mixture of NaBH (51.2%) containing sodium borohydride and boric oxide (molecular ratio about 2:1) in form of tablets of a diameter of 9 mm. and a height of 6 mm.; the tablets had been prepared under a pressure of about 4 to 6 tons. The tablets contained tributyl phosphate as anti-foaming agent as well as 0.4% per weight of talcum. The drying column was filled with 320 g. of technical granulated calcium chloride (the diameter of the particles was larger than 5 mm.). The entire generator was then immersed into water of 20 C. down to a depth of about 450 mm. (measured from the lower end of the generator jacket). After about 30 seconds the evolution of hydrogen set in under controlled conditions and in the course of a further 8 minutesthe reaction velocity appreciably slowed down-hydrogen was produced in a total quantity of 2.04 m. (at 20 C.) and with a mean temperature of 30 C. (measured at the end of a 2 m. long rubber tubing fastened to the drying column). This corresponds to a yield of 90.5%.

Example 4 The process described in Example 3 was repeated. However, the generator was immersed into water of 10 C.; the other processing conditions remained unchanged. In the course of totally 8 /2 minutes 2.08 m. (at 20 C.) of hydrogen of a mean temperature of 27 C. were obtained; yield 92.3%.

Example 5 The process described in Example 3 was repeated, however, the reaction chamber was charged with 870 g. of a mixture of sodium borohydride and boric oxide in tablet form. Water previously filled into the reaction chamber had a temperature of 20 C.; the other processing conditions remained unchanged. About 4.5 minutes after immersion of the generator into water the evolution of hydrogen set in under controlled conditions and in the course of a further 5 minutes 1.035 m? (at 21 C.) of hydrogen were totally produced; yield 91%.

Example 6 The process described in Example 5 was repeated; however, the water filled into the reaction chamber had a tem perature of +5 C.; the other processing conditions remained unchanged. In the course of totally 6 minutes 0.975 m. (at 20 C.) of hydrogen of a mean temperature of 22 C. were obtained. The yield of hydrogen amounted to 86.9%.

Example 7 1480 g. of calcium carbide in form of lumps (edge length 7 to 15 mm.) were filled into the reaction chamber of the apparatus described in Example 3 and shown in FTGURE 11; then the apparatus was immersed into water of 20 C. about 450 mm. below the surface level of the water, while the drying column was not filled. In the course of totally 6 minutes 410 litres of acetylene (mean temperature 23 C.) were obtained. This corresponds to a yield of 91.5% of the theoretical.

Example 8 2230 g. of lumpy calcium carbonate (average edge length about 10 to 15 mm.) were fed into a corrosionresistant apparatus (shown in FIGURE 11), and the entire apparatus was immersed into hydrochloric acid 1 1 (about 20%) of about 15 C. about 450 mm. below the surface level of the liquid, while the drying column was not filled. In the course of totally 25 minutes 505 litres of carbon dioxide (mean temperature 8 C.) were obtained. This corresponds to a yield of 98% of the theoretical.

Example 9 Example 10 445 g. of calcium carbonate in form of lumps (edge length 10 to mm.) were fed into a corrosion-resistant apparatus (cf. FIGURE 10). The entire apparatus was then immersed into about hydrochloric acid of about 28 C. about 400 mm. below the surface level, While the drying column was not filled. 106 litres of carbon dioxide (mean temperature 23 C.) were obtained within 5 minutes. Yield 97.5% of the theoretical.

We claim: 1. Apparatus for the production of gases by reaction of solids and liquids comprising at least one generator vessel and a washing vessel being connected to said generator vessel via a gas pipe, said generator vessel having at least one reaction chamber, said reaction chamber being-provided with at least one substantially vertically extended,

perforated tube disposed within the reaction chamber and being open at the bottom for passage of water upwardly thereinto, the perforations being disposed along the tube for passage of water radially outwardly from within the tube into the reaction chamber, solid reactant for said reaction with liquid disposed in the reaction chamber about the and outwardly of said tube, at least one substantially horizontally extended plate, which is arranged below said reaction chamber and which is provided at least one bore, said bore being misaligned with the said open bottom of the perforated tube and said horizontal plate having an imperforate portion thereof disposed for intercepting solid particles passing through perforations in the tube and falling downwardly through the tube, said washing vessel being equipped with a spray water separator, a gas outlet means and a drying column, said gas pipe being immersed into said washing .Vessel.

2. Apparatus as claimed in claim 1, comprlsing said generator vessel and said washing vessel being arranged separately from one another.

3. Apparatus as claimed in claim 1, comprising said generator vessel being surrounded by said washing vessel.

4. Apparatus as claimed in claim 1, comprising said 12 generator vessel being concentrically surrounded by said washing vessel.

5. Apparatus as claimed in claim 1, comprising a reaction assembly consisting of said reaction chamber, a housing for said reaction chamber, said perforated tube, at least one substantially horizontally extended plate at least one here and being constructed as an independent unit which can be removed from said generator vessel.

6. Apparatus for the production of gases by reaction of solids and liquids comprising at least one generator vessel and a washing vessel being connected to said generator vessel via a gas pipe, said generator vessel having at least one reaction chamber, said reaction chamber being provided with at least one substantially vertically extended, perforated tube, a sinkable float disposed below said reaction chamber and within the generator vessel, means fixedly mounting the reaction chamber on the sinkable float, the upper surface and the bottom surface of the sinkable float each having at least one opening, whereby when the apparatus carrying a solid in the reaction chamber is placed in a liquid for reaction of the solid and liquid for generation of gas, the sinkable float initially floats on the surface of the liquid holding the solid in the reaction chamber out of contact with the liquid, said washing vessel being equipped with a spray water separator, a gas outlet means and a drying column, said gas pipe extending downwardly in the washing vessel for delivery of gas to below the level of liquid present in the washing vessel when the apparatus is placed in liquid for generation of gas.

7. Apparatus as claimed in claim 6, said sinkable float having a removable cover on the bottom side thereof.

8. Apparatus as claimed in claim 6, and including a removable locking bar secured to the generator vessel 'below the reaction chamber and sinkable float, for limiting downward movement of the reaction chamber and hollow body in the generator vessel.

References Cited UNITED STATES PATENTS 646,404 3/ 1900 Yvonneau 4814 651,684 6/1900 Westman 23-150 977,442 12/1910 Foersterling et al. 23211 1,700,578 l/1929 Bacon 23181 1,729,043 9/1929 Kemmerich 23219 2,114,144 4/1938 Kamann 23282 2,334,211 11/1943 Miller 23282 2,404,599 7/1946 Sanderson 260-676 2,623,812 12/1952 Eborall et a1. 23281 X 2,772,952 12/1956 Jacobs 2328l 3,134,643 5/1964 Clusius 23-157 MORRIS O. WOLK, Primary Examiner MAURICE A. BRINDISI, JAMES H. TAYMAN, JR.,

E. STERN, Assistant Examiners. 

1. APPARATUS FOR THE PRODUCTION OF GASES BY REACTION OF SOLIDS AND LIQUIDS COMPRISING AT LEAST ONE GENERATOR VESSEL AND A WASHING VESSEL BEING CONNECTED TO SAID GENERATOR VESSEL VIA A GAS PIPE, SAID GENERATOR VESSEL HAVING AT LEAST ONE REACTION CHAMBER, SAID REACTION CHAMBER BEING PROVIDED WITH AT LEAST ONE SUBSTANTIALLY VERTICALLY EXTENDED PERFORATED TUBE DISPOSED WITHIN THE REACTION CHAMBER AND BEING OPEN AT THE BOTTOM FOR PASSAGE OF WATER UPWARDLY THEREINTO, THE PERFORATIONS BEING DISPOSED ALONG THE TUBE FOR PASSAGE OF WATER RADIALLY OUTWARDLY FORM WITHIN THE TUBE INTO THE REACTION CHAMBER, AND SOLID REACTANT FOR SAID REACTION WITH LIQUID DISPOSED INTHE REACTION CHAMBER ABOUT THE AND OUTWARDLY OF SAID TUBE, AT LEAST ONE SUBSTANTIALLY HORIZONTALLY EXTENDED PLATE, WHICH IS ARRANGED BELOW SAID REACTION CHAMBER AND WHICH IS PROVIDED AT LEAST ONE BORE, SAID BORE BEING MISALIGNED WITH THE SAID OPEN BOTTOM OF THE PERFORATED TUBE AND SAID HORIZONTAL PLATE HAVING AN IMPERFORATE PORTION THEREOF DISPOSED FOR INTERCEPTING SOLID PARTICLES PASSING THROUGH PERFORATIONS IN THE TUBE AND FALLING DOWNWARDLY THROUGH THE TUBE, SAID WASHING VESSEL BEING EQUIPPED WITH A SPRAY WATER SEPARATOR, A GAS OUTLET MEANS AND A DRYING COLUMN, SAID GAS PIPE BEING IMMERSED INTO SAID WASHING VESSEL. 